Substrate processing method and substrate processing system

ABSTRACT

A substrate processing method includes: preparing a substrate which includes a base having an epitaxial layer formed by epitaxial growth, and an insulating film formed on the base and having a penetration portion that exposes the epitaxial layer; forming a silicon film on a surface of the epitaxial layer exposed from the penetration portion rather than a side wall of the penetration portion; and forming a metal film on the silicon film formed on the surface of the epitaxial layer rather than the side wall of the penetration portion, and causing the silicon film to react with the metal film to form a metal silicide film.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2021-157218, filed on Sep. 27, 2021, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing method and asubstrate processing system.

BACKGROUND

Patent Document 1 discloses an oxide film removing method of removing anatural oxide film formed on a surface of silicon at a bottom of apattern such as a contact hole or a trench. In addition, Patent Document1 discloses a contact forming method, in which a metal film is formedafter removing the natural oxide film, and the silicon at the bottom ofthe pattern is caused to react with the metal film to form a contact atthe bottom of the pattern.

PRIOR ART DOCUMENT [Patent Document]

-   Patent Document 1: Japanese Patent Laid-Open Publication No.    2018-148193

SUMMARY

According to one embodiment of the present disclosure, a substrateprocessing method includes: preparing a substrate which includes a basehaving an epitaxial layer formed by epitaxial growth, and an insulatingfilm formed on the base and having a penetration portion that exposesthe epitaxial layer; forming a silicon film on a surface of theepitaxial layer exposed from the penetration portion rather than a sidewall of the penetration portion; and forming a metal film on the siliconfilm formed on the surface of the epitaxial layer rather than the sidewall of the penetration portion, and causing the silicon film to reactwith the metal film to form a metal silicide film

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentdisclosure, and together with the general description given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present disclosure.

FIG. 1 is a schematic view illustrating a configuration example of asubstrate processing system.

FIG. 2 is an example of a schematic view illustrating a configurationexample of a processing apparatus.

FIG. 3 is an example of a schematic view illustrating a configurationexample of a processing apparatus.

FIG. 4 is an example of a schematic view illustrating a configurationexample of a processing apparatus.

FIG. 5 is an example of a flowchart illustrating a substrate processingmethod by the substrate processing system.

FIGS. 6A to 6E are examples of cross-sectional views of a substrate inrespective processes.

FIGS. 7A and 7B are examples of a graph showing a result of forming a Sifilm in the process illustrated in step S104.

FIG. 8 is a graph showing an example of etching rates of an amorphoussilicon film and a crystalline silicon film.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. In the followingdetailed description, numerous specific details are set forth in orderto provide a thorough understanding of the present disclosure. However,it will be apparent to one of ordinary skill in the art that the presentdisclosure may be practiced without these specific details. In otherinstances, well-known methods, procedures, systems, and components havenot been described in detail so as not to unnecessarily obscure aspectsof the various embodiments.

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings. In each drawing, the same orcorresponding components may be denoted by the same reference numerals,and a description thereof may be omitted.

[Substrate Processing System]

A substrate processing system according to an embodiment will bedescribed with reference to FIG. 1 . FIG. 1 is a schematic viewillustrating an exemplary configuration of a substrate processingsystem.

As illustrated in FIG. 1 , the substrate processing system includesprocessing apparatuses 101 to 104, a vacuum transfer chamber 200,load-lock chambers 301 to 303, an atmospheric transfer chamber 400, andload ports 501 to 503, and a controller 600.

The processing apparatuses 101 to 104 are connected to the vacuumtransfer chamber 200 via gate valves G11 to G14, respectively. Interiorsof the processing apparatuses 101 to 104 are depressurized to apredetermined vacuum atmosphere, and each of the processing apparatuses101 to 104 performs therein a desired process on a substrate W such as awafer, respectively. The processing apparatus 101 is an apparatusconfigured to remove a natural oxide film formed at a bottom of a recessin the substrate W. The processing apparatus 102 is an apparatusconfigured to selectively form a silicon film (hereinafter, alsoreferred to as a “Si film”) at the bottom of the recess in the substrateW. The processing apparatus 103 is an apparatus configured toselectively form a metal silicide film at the bottom of the recess inthe substrate W by forming a metal film on the substrate W. Theprocessing apparatus 104 may be an apparatus which is the same as any ofthe processing apparatuses 101 to 103, or may be an apparatus thatperforms a separate process. The processing apparatuses 101 to 103 willbe described later with reference to FIGS. 2 to 4 .

An interior of the vacuum transfer chamber 200 is depressurized to apredetermined vacuum atmosphere. The vacuum transfer chamber 200 isprovided with a transfer mechanism 201 capable of transferring thesubstrate W in a depressurized state. The transfer mechanism 201transfers the substrate W with respect to the processing apparatuses 101to 104 and the load-lock chambers 301 to 303. The transfer mechanism 201includes, for example, two transfer arms 202 a and 202 b.

The load-lock chambers 301 to 303 are connected to the vacuum transferchamber 200 via gate valves G21 to G23, respectively, and connected tothe atmospheric transfer chamber 400 via the gate valves G31 to G33,respectively. Interiors of the load-lock chambers 301 to 303 areconfigured to be switchable between atmospheric atmosphere and vacuumatmospheres.

Interior of the atmospheric transfer chamber 400 has atmosphericatmosphere and, for example, a downflow of clean air is formed in theatmospheric transfer chamber 400. In the atmospheric transfer chamber400, an aligner 401 is provided to perform alignment of the substrate W.In addition, the atmospheric transfer chamber 400 is provided with atransfer mechanism 402. The transfer mechanism 402 transfers thesubstrate W with respect to the load-lock chambers 301 to 303, carriersC in the load ports 501 to 503 to be described later, and the aligner401.

The load ports 501 to 503 are provided in a wall surface of a long sideof the atmospheric transfer chamber 400. A carrier C accommodating thesubstrate W, or an empty carrier C is attached in each of the load ports501 to 503. As the carriers C, for example, front opening unified pods(FOUPs) may be used.

The controller 600 controls respective components of the substrateprocessing system. For example, the controller 600 executes operationsof the processing apparatuses 101 to 104, operations of the transfermechanisms 201 and 402, opening and closing of the gate valves G11 toG14, G21 to G23, and G31 to G33, and switching of the atmospheres in theload-lock chambers 301 to 303. The controller 600 may be, for example, acomputer.

In addition, the configuration of the substrate processing system is notlimited to those described above. The substrate processing system may beconfigured to have a batch type apparatus configured to process aplurality of substrates W in a single processing apparatus. In addition,the vacuum transfer chamber may have a configuration in which the batchtype apparatus is connected to the vacuum transfer chamber via a gatevalve, or may have a configuration in which a plurality of vacuumtransfer devices is provided in the vacuum transfer chamber.

[Processing Apparatus 101]

Next, the processing apparatus 101 will be described with reference toFIG. 2 . FIG. 2 is an example of a schematic view illustrating aconfiguration example of the processing apparatus 101. The processingapparatus 101 is an apparatus configured to remove a natural oxide filmformed at the bottom of the recess in the substrate W within theprocessing container 1 under a depressurized state.

As illustrated in FIG. 2 , the processing apparatus 101 includes theprocessing container 1, a stage 2, a shower head 3, an exhauster 4, agas supply mechanism 5, an RF power supply 8, and a controller 9.

The processing container 1 is made of a metal such as aluminum, and hasa substantially cylindrical shape. The processing container 1accommodates the substrate W. A load/unload port 11 is formed in a sidewall of the processing container 1 for loading and unloading thesubstrate W, and is opened and closed by a gate valve 12 (the gate valveG11 illustrated in FIG. 1 ). An annular exhaust duct 13 having arectangular cross section is provided on a main body of the processingcontainer 1. A slit 13 a is formed along an inner peripheral surface ofthe exhaust duct 13. An exhaust port 13 b is formed in the outer wall ofthe exhaust duct 13. On a top surface of the exhaust duct 13, a ceilingwall 14 is provided to close an upper opening of the processingcontainer 1 via an insulator 16. A space between the exhaust duct 13 andthe insulator 16 is hermetically sealed with a seal ring 15. A partition17 partitions an interior of the processing container 1 into upper andlower portions when the stage 2 (and a cover 22) is raised to aprocessing position.

The stage 2 horizontally supports the substrate W in the processingcontainer 1. The stage 2 is formed in a disk shape having a sizecorresponding to the substrate W, and is supported by a support 23. Thestage 2 is formed of a ceramic material such as A1N or a metallicmaterial such as aluminum or nickel alloy, and a heater 21 configured toheat the substrate W is embedded in the stage 2. The heater 21 generatesheat by being fed with power from a heater power supply (notillustrated). The substrate W is controlled to a predeterminedtemperature by controlling an output of the heater 21 by a temperaturesignal of a thermocouple (not illustrated) provided in a vicinity of atop surface of the stage 2. The stage 2 may include an electrostaticchuck configured to electrostatically attract the substrate W. Byproviding the electrostatic chuck, the substrate W is electrostaticallyattracted to a surface of the stage 2, and thus it is possible tocontrol the temperature of the substrate W with high accuracy. Inaddition, the stage 2 may be provided with a flow path therein, so thata temperature control coolant from outside may flow and circulatethrough the flow path. The stage 2 is provided with the cover 22 formedof ceramic such as alumina to cover an outer peripheral region of thetop surface and a side surface of the stage 2.

The support 23 that supports the stage 2 is provided on a bottom surfaceof the stage 2. The support 23 extends downward from a center of thebottom surface of the stage 2 to below the processing container 1 via ahole formed in a bottom wall of the processing container 1, and a lowerend of the support 23 is connected to a lifting mechanism 24. The stage2 is raised and lowered, by the lifting mechanism 24 via the support 23,between the processing position illustrated in FIG. 2 and a transferposition, which is indicated by the alternating long and two shortdashes line below the processing position, and at which the substrate Wis capable of being transferred. A flange 25 is provided on the support23 below the processing container 1, and a bellows 26, which partitionsan atmosphere in the processing container 1 from the outside air, isprovided between a bottom surface of the processing container 1 and theflange 25 to expand and contract in response to a vertical movement ofthe stage 2.

Three substrate support pins 27 (only two of which are illustrated) areprovided in a vicinity of the bottom surface of the processing container1 to protrude upward from a lifting plate 27 a. The substrate supportpins 27 are raised and lowered by a lifting mechanism 28 provided belowthe processing container 1 via the lifting plate 27 a. The substratesupport pins 27 are configured to be inserted into through-holes 2 aformed in the stage 2 located at the transfer position, and areconfigured to protrude and sink with respect to the top surface of thestage 2. By raising and lowering the substrate support pins 27, adelivery of the substrate W is performed between a transfer mechanism(not illustrated) and the stage 2.

The shower head 3 supplies a processing gas into the processingcontainer 1 in a shower form. The shower head 3 is made of a metal andprovided to face the stage 2, and has a diameter, which is substantiallyequal to that of the stage 2. The shower head 3 includes a main body 31fixed to the ceiling wall 14 of the processing container 1 and a showerplate 32 connected below the main body 31. A gas diffusion space 33 isformed between the main body 31 and the shower plate 32. In the gasdiffusion space 33, a gas introduction hole 36 is provided to penetratecenters of the main body 31 and the ceiling wall 14 of the processingcontainer 1. An annular protrusion 34 protruding downward is formed on aperipheral edge of the shower plate 32. Gas ejection holes 35 are formedin a flat surface inward of the annular protrusion 34. In a state inwhich the stage 2 is located at the processing position, a processingspace 38 is formed between the stage 2 and the shower plate 32, and atop surface of the cover 22 and the annular protrusion 34 become closeto each other so as to form an annular gap 39.

The exhauster 4 evacuates an interior of the processing container 1. Theexhauster 4 includes an exhaust pipe 41 connected to the exhaust port 13b, and an exhaust mechanism 42 connected to the exhaust pipe 41 andhaving a vacuum pump, a pressure control valve, or the like. During aprocessing, a gas in the processing container 1 reaches the exhaust duct13 via the slit 13 a, and is exhausted from the exhaust duct 13 via theexhaust pipe 41 by the exhaust mechanism 42.

The gas supply mechanism 5 supplies the processing gas into theprocessing container 1. The gas supply mechanism 5 includes a gas supply50 a.

The gas supply 50 a supplies an etching gas into the processingcontainer 1 via a gas line 50 b. A halogen-containing gas (e.g., C₄F₈gas, HF gas, CF₄ gas), NH₃ gas, H₂ gas, an inert gas, or the like aresupplied into the processing container 1 as the etching gas.

The gas line 50 b is provided with a flow rate controller 50 c and avalve 50 d from an upstream side. A downstream side of the valve 50 d ofthe gas line 50 b is connected to the gas introduction hole 36. A gassupplied from the gas supply 50 a is supplied into the processingcontainer 1. A supply and stop of the gas from the gas supply 50 a tothe processing container 1 is performed by opening and closing the valve50 d.

In addition, the processing apparatus 101 is a capacitively coupledplasma apparatus, in which the stage 2 serves as a lower electrode andthe shower head 3 serves as an upper electrode. The stage 2 serving asthe lower electrode is grounded via a capacitor (not illustrated).

Radio frequency power (hereinafter, also referred to as “RF power”) isapplied to the shower head 3 serving as the upper electrode by the RFpower supply 8. The RF power supply 8 includes a feed line 81, a matcher82, and a radio frequency power source 83. The radio frequency powersource 83 is a power source that generates radio frequency power. Radiofrequency power has a frequency appropriate for plasma generation. Thefrequency of the radio frequency power is, for example, a frequencywithin a range of 450 KHz to 100 MHz. The radio frequency power source83 is connected to the main body 31 of the shower head 3 via the matcher82 and the feed line 81. The matcher 82 includes a circuit configured tomatch an output reactance of the radio frequency power source 83 and areactance of a load (the upper electrode). Although the RF power supply8 has been described as applying radio frequency power to the showerhead 3 serving as the upper electrode, the present disclosure is notlimited thereto. The RF power supply 8 may be configured to apply radiofrequency power to the stage 2 serving as the lower electrode.

The controller 9 is, for example, a computer, and includes a centralprocessing unit (CPU), a random access memory (RAM), a read only memory(ROM), an auxiliary storage device, and the like. The RAM, ROM, andauxiliary storage device may be computer readable storage devices. TheCPU operates based on a program stored in the ROM or the auxiliarystorage device, and controls an operation of the processing apparatus101. The controller 9 may be provided either inside or outside theprocessing apparatus 101. In the case in which the controller 9 isprovided outside the processing apparatus 101, the controller 9 iscapable of controlling the processing apparatus 101 via a wired orwireless communication mechanism.

[Processing Apparatus 102]

Next, the processing apparatus 102 will be described with reference toFIG. 3 . FIG. 3 is an example of a schematic view illustrating aconfiguration example of the processing apparatus 102. The processingapparatus 102 is an apparatus configured to selectively form a Si filmat the bottom of the recess in the substrate W within the processingcontainer 1 under a depressurized state.

As illustrated in FIG. 3 , the processing apparatus 102 includes aprocessing container 1, a stage 2, a shower head 3, an exhauster 4, agas supply mechanism 5, and a controller 9. In the processing apparatus102, a description of a configuration overlapping with that of theprocessing apparatus 101 (see FIG. 2 ) will be omitted.

The gas supply mechanism 5 supplies a processing gas into the processingcontainer 1. The gas supply mechanism 5 includes a silicon-containinggas supply 51 a, a halogen-containing gas supply 52 a, and an inert gassupply 55 a.

The silicon-containing gas supply 51 a supplies a silicon-containing gasinto the processing container 1 via a gas line 51 b. As thesilicon-containing gas, for example, a gas containing at least oneselected from the group of SiH₄ gas, Si₂H₆ gas, SiH₂Cl₂ gas, Si₃H₈ gas,Si₄H₁₀ gas, and the like may be used.

The gas line 51 b is provided with a flow rate controller 51 c and avalve 51 d from an upstream side. A downstream side of the valve 51 d ofthe gas line 51 b is connected to a gas introduction hole 36 via a gasline 57. The silicon-containing gas supplied from the silicon-containinggas supply 51 a is supplied into the processing container 1. A supplyand stop of the silicon-containing gas from the silicon-containing gassupply 51 a to the processing container 1 is performed by opening andclosing the valve 51 d.

The halogen-containing gas supply 52 a supplies a halogen-containing gasinto the processing container 1 via a gas line 52 b. As thehalogen-containing gas, for example, a gas containing at least oneselected from the group of Cl₂ gas, HBr gas, ClF₃ gas, and the like maybe used.

The gas line 52 b is provided with a flow rate controller 52 c and avalve 52 d from an upstream side. A downstream side of the valve 52 d ofthe gas line 52 b is connected to the gas introduction hole 36 via thegas line 57. The halogen-containing gas supplied from thehalogen-containing gas supply 52 a is supplied into the processingcontainer 1. A supply and stop of the halogen-containing gas from thehalogen-containing gas supply 52 a to the processing container 1 isperformed by opening and closing the valve 52 d.

The inert gas supply 55 a supplies an inert gas into the processingcontainer 1 via a gas line 55 b. As the inert gas, for example, Ar gasor the like may be used.

The gas line 55 b is provided with a flow rate controller 55 c and avalve 55 d from an upstream side. A downstream side of the valve 55 d ofthe gas line 55 b is connected to the gas introduction hole 36 via thegas line 57. The inert gas supplied from the inert gas supply 55 a issupplied into the processing container 1. A supply and stop of the inertgas from the inert gas supply 55 a to the processing container 1 isperformed by opening and closing the valve 55 d.

[Processing Apparatus 103]

Next, the processing apparatus 103 will be described with reference toFIG. 4 . FIG. 4 is an example of a schematic view illustrating aconfiguration example of the processing apparatus 103. The processingapparatus 103 is an apparatus configured to form a metal film on thesubstrate W within the processing container 1 under a depressurizedstate. By forming the metal film, a metal silicide film is selectivelyformed at the bottom of the recess of the substrate W.

As illustrated in FIG. 4 , the processing apparatus 103 includes aprocessing container 1, a stage 2, a shower head 3, an exhauster 4, agas supply mechanism 5, an RF power supply 8, and a controller 9. In theprocessing apparatus 102, a description of a configuration overlappingwith that of the processing apparatus 101 (see FIG. 2 ) will be omitted

The gas supply mechanism 5 supplies a processing gas into the processingcontainer 1. The gas supply mechanism 5 includes a metal-containing gassupply 53 a, a reducing gas supply 54 a, and an inert gas supply 56 a.

The metal-containing gas supply 53 a supplies a metal-containing gasinto the processing container 1 via a gas line 53 b. As themetal-containing gas, for example, a gas containing at least oneselected from the group of TiCl₄ gas, TiBr₄ gas, and the like may beused.

The gas line 53 b is provided with a flow rate controller 53 c and avalve 53 d from an upstream side. A downstream side of the valve 53 d ofthe gas line 53 b is connected to the gas introduction hole 36 via a gasline 57. The metal-containing gas supplied from the metal-containing gassupply 53 a is supplied into the processing container 1. A supply andstop of the metal-containing gas from the metal-containing gas supply 53a to the processing container 1 is performed by opening and closing thevalve 53 d.

The reducing gas supply 54 a supplies a reducing gas into the processingcontainer 1 via a gas line 54 b. As the reducing gas, for example, H₂gas or the like may be used.

The gas line 54 b is provided with a flow rate controller 54 c and avalve 54 d from an upstream side. A downstream side of the valve 54 d ofthe gas line 54 b is connected to the gas introduction hole 36 via thegas line 57. The reducing gas supplied from the reducing gas supply 54 ais supplied into the processing container 1. A supply and stop of thereducing gas from the reducing gas supply 54 a to the processingcontainer 1 is performed by opening and closing the valve 54 d.

The inert gas supply 56 a supplies an inert gas into the processingcontainer 1 via a gas line 56 b. As the inert gas, for example, Ar gasor the like may be used.

The gas line 56 b is provided with a flow rate controller 56 c and avalve 56 d from an upstream side. A downstream side of the valve 56 d ofthe gas line 56 b is connected to the gas introduction hole 36 via thegas line 57. The inert gas supplied from the inert gas supply 56 a issupplied into the processing container 1. A supply and stop of the inertgas from the inert gas supply 56 a to the processing container 1 isperformed by opening and closing the valve 56 d.

[Substrate Processing Method]

Next, a substrate processing method performed by the substrateprocessing system according to an embodiment will be described withreference to FIGS. 5 to 6E. FIG. 5 is an example of a flowchartillustrating a substrate processing method performed by the substrateprocessing system. FIGS. 6A to 6E are examples of cross-sectional viewsof a substrate W in respective processes.

In step S101, the controller 600 prepares a substrate W. The controller600 controls the transfer mechanism 402 and the gate valve G31 totransfer the substrate W accommodated in a carrier C to the load-lockchamber 301 in the atmospheric atmosphere via the atmospheric transferchamber 400. The controller 600 controls the load-lock chamber 301 todepressurize the interior of the load-lock chamber 301 to a vacuumatmosphere. The controller 600 controls the transfer mechanism 201 andthe gate valves G21 and G11 to transfer the substrate W from theload-lock chamber 301 to the processing apparatus 101 and place thesubstrate W on the stage 2 of the processing apparatus 101. Thereafter,the controller 9 of the processing apparatus 101 controls the liftingmechanism 24 to lift the stage 2 from the transfer position to theprocessing position.

Here, FIG. 6A illustrates an example of the prepared substrate W. Thesubstrate W has a base 700 and an insulating film 710 formed on the base700. The base 700 is made of, for example, Si or SiGe. The insulatingfilm 710 is made of, for example, SiN or SiO₂. A penetration portion 720is formed in the insulating film 710 so as to expose a surface of thebase 700. That is, a recess is formed in the surface of the substrate W,and the surface of the base 700 is exposed at a bottom portion of therecess.

The base 700 includes an epitaxial layer 701 which is a crystallinesilicon film formed by epitaxial growth. For example, in a fin-typechannel field effect transistor, a source and a drain are formed byepitaxially growing Si or SiGe. In addition, a natural oxide film 702 isformed on the surface of the base 700 exposed from the penetrationportion 720 (the bottom portion of the recess).

In step S102, the controller 600 controls the processing apparatus 101to remove the natural oxide film 702 formed on the surface of the base700 exposed from the penetration portion 720.

In the processing apparatus 101, for example, the RF power supply 8applies radio frequency power to the shower head 3 serving as the upperelectrode, and an etching gas (e.g., C₄F₈ gas), an inert gas, or thelike is supplied from the gas supply 50 a into the processing container1, so that the natural oxide film 702 on the substrate W is removed byplasma etching. Alternatively, the processing apparatus 101 supplies anetching gas (e.g., HF gas) and a reactive gas (e.g., NH₃ gas) into theprocessing container 1 from the gas supply 50 a, so that the naturaloxide film 702 on the substrate W is removed by chemical etching. Themethod of removing the natural oxide film 702 performed in theprocessing apparatus 101 is not limited to those described above.

Here, FIG. 6B illustrates an example of the substrate W from which thenatural oxide film 702 has been removed. By removing the natural oxidefilm 702, the surface of the base 700 exposed from the penetrationportion 720 exposes a surface of the epitaxial layer 701, which is acrystalline silicon film.

In step S103, the controller 600 vacuum-transfers the substrate W fromthe processing apparatus 101 to the processing apparatus 102. Thecontroller 9 of the processing apparatus 101 controls the liftingmechanism 24 to lower the stage 2 from the processing position to thetransfer position. The controller 600 controls the transfer mechanism201 and the gate valves G11 and G12 to transfer the substrate W from theprocessing apparatus 101 to the processing apparatus 102, and place thesubstrate W on the stage 2 of the processing apparatus 102. Thereafter,the controller 9 of the processing apparatus 102 controls the liftingmechanism 24 to lift the stage 2 from the transfer position to theprocessing position.

In step S104, the controller 600 controls the processing apparatus 102to form a Si film on the substrate W.

In the processing apparatus 102, for example, a silicon-containing gas(e.g., monosilane (SiH₄) gas, disilane (Si₂H₆) gas, trisilane (Si₃H₈)gas, tetrasilane (Si₄H₁₀) gas, or a chlorine-containing gas such aschlorine monochlorosilane (SiH₃Cl) gas, dichlorosilane (SiH₂C₂) gas,trichlorosilane (SiHCl₃) gas, silicon tetrachloride (SiCl₄) gas, andhexachlorodisilane (Si₂Cl₆) gas) is supplied from the silicon-containinggas supply 51 a into the processing container 1, so that a Si film isformed on the substrate W.

Here, FIG. 6C illustrates an example of the substrate W on which a Sifilm is formed by a process performed by the processing apparatus 102.

The epitaxial layer 701 made of Si or SiGe has been formed at the bottomportion of the recess. Therefore, at the bottom portion of the recess, acrystalline silicon film is formed by epitaxial growth from theepitaxial layer 701. Thus, it is possible to increase a film thicknessof the epitaxial layer 701. On the other hand, an amorphous silicon film703 is formed on a top surface of the insulating film 710 made of SiN orSiO₂ and on a side wall of the penetration portion 720. Due to theaforementioned difference in a base on which a Si film is formed, thecrystalline silicon film (epitaxial layer 701) may be formed at thebottom portion of the recess, and the amorphous silicon film 703 may beformed on the side and top surfaces of the recess.

FIGS. 7A and 7B are examples of a graph showing a result of forming a Sifilm in the process illustrated in step S104. FIG. 7A shows a case wherea Si film was formed on a Si base, and FIG. 7B shows a case where a Sifilm was formed on a SiGe base. Formation of the Si films was confirmedby an EDX analysis was performed with the horizontal axis representing adepth (nm) and the vertical axis representing a concentration (At %) ofelements.

The Si films were formed under a condition including a stage temperatureof 500 degrees C. to 600 degrees C., a pressure of 1 Torr to 10 Torr,Si₂H₆ gas as the silicon-containing gas of 10 sccm to 100 sccm, and Argas as the inert gas of 100 sccm to 5,000 sccm.

From the results of FIGS. 7A and 7B, it could be recognized that Sifilms can be formed on both the Si and SiGe bases.

When Si₂H₆ gas is used as the silicon-containing gas, by controlling thetemperature of the substrate W from 400 degrees C. to 580 degrees C.during the formation of the Si film, a crystalline silicon film isformed on the surface of the epitaxial layer 701 (at the bottom portionof the recess), and an amorphous silicon film is formed on the topsurface of the insulating film 710 and the side wall of the penetrationportion 720 (the side wall of the recess). When Si₄H₁₀ gas is used asthe silicon-containing gas, by controlling the temperature of thesubstrate W from 350 degrees C. to 480 degrees C., a crystalline siliconfilm is formed on the surface of the epitaxial layer 701 (at the bottomportion of the recess), and an amorphous silicon film is formed on thetop surface of the insulating film 710 and the side wall of thepenetration portion 720 (the side wall of the recess).

Returning to FIGS. 5 to 6E, in step S105, the controller 600 controlsthe processing apparatus 102 to selectively etch the amorphous siliconfilm 703.

The processing apparatus 102 supplies, for example, a halogen-containinggas (e.g., Cl₂ gas, HBr gas, or ClF₃ gas) from the halogen-containinggas supply 52 a into the processing container 1, so that the Si filmformed on the substrate W is chemically etched.

Here, etching rates of the amorphous silicon film and the crystallinesilicon film will be described with reference to FIG. 8 . FIG. 8 is agraph showing an example of etching rates of an amorphous silicon filmand a crystalline silicon film. The horizontal axis represents areciprocal of temperature 1000/T [1/Degrees C.]. The vertical axisrepresents an etching rate [nm/min]. The etching rate of the amorphoussilicon film (a-Si) is indicated by the solid line, and the etching rateof the crystalline silicon film (EpiSi) is indicated by the broken line.

Here, the amorphous silicon film and the crystalline silicon film werechemically etched by using Cl₂ gas as the halogen-containing gas. In theexample shown in the graph of FIG. 8 , the etching rate of the amorphoussilicon film is substantially ten times the etching rate of thecrystalline silicon film. Thus, it is possible for the processingapparatus 102 to selectively etch the amorphous silicon film 703.

Here, FIG. 6D shows an example of the substrate W in which the amorphoussilicon film 703 is selectively etched by the process performed by theprocessing apparatus 102. The amorphous silicon film 703 formed on thetop surface of the insulating film 710 and the side wall of thepenetration portion 720 is etched.

As described above, it is possible to selectively form the crystallinesilicon film at the bottom portion of the recess by the processes ofsteps S104 and S105.

In addition, although the process of supplying the silicon-containinggas illustrated in step S104 and the process of supplying thehalogen-containing gas illustrated in step S105 have been described asbeing sequentially performed, the present disclosure is not limitedthereto.

For example, the silicon-containing gas and the halogen-containing gasmay be supplied simultaneously. With such a configuration, it ispossible to form the crystalline silicon film (epitaxial layer 701) atthe bottom portion of the recess while suppressing formation of theamorphous silicon film 703 on the top surface of the insulating film 710and the side wall of the penetration portion 720.

In addition, the process of supplying the silicon-containing gasillustrated in step S104 and the process of supplying thehalogen-containing gas illustrated in step S105 may be repeated. Withsuch a configuration, it is possible to selectively form the crystallinesilicon film at the bottom portion of the recess.

In step S106, the controller 600 vacuum-transfers the substrate W fromthe processing apparatus 102 to the processing apparatus 103. Thecontroller 9 of the processing apparatus 102 controls the liftingmechanism 24 to lower the stage 2 from the processing position to thetransfer position. The controller 600 controls the transfer mechanism201 and the gate valves G12 and G13 to transfer the substrate W from theprocessing apparatus 102 to the processing apparatus 103, and place thesubstrate W on the stage 2 of the processing apparatus 103. Thereafter,the controller 9 of the processing apparatus 103 controls the liftingmechanism 24 to lift the stage 2 from the transfer position to theprocessing position.

In step S107, the controller 600 controls the processing apparatus 103to form a metal film (Ti film) on the substrate W.

For example, the processing apparatus 103 supplies a metal-containinggas (e.g., TiCl₄ gas or TiBr₄ gas) into the processing container 1 fromthe metal-containing gas supply 53 a, supplies a reducing gas (e.g., H₂gas) into the processing container 1 from the reducing gas supply 54 a,and supplies an inert gas (e.g., Ar gas) into the processing container 1from the inert gas supply 56 a. Thereafter, radio frequency power isapplied to the shower head 3 serving as the upper electrode by the RFpower supply 8 to generate plasma, and the substrate W is exposed to thegenerated plasma, whereby a metal film (Ti film) is formed on thesubstrate W by a chemical vapor deposition (CVD) reaction.

Here, the metal film (e.g., Ti film) is formed on the epitaxial layer701 at the bottom portion of the recess. The metal film reacts with theepitaxial layer 701 and forms a metal silicide film (TiSi film) 730 in aself-aligning manner (see FIG. 6E).

In addition, the metal film (Ti film) formed on the top surface of theinsulating film 710 and the side wall of the penetration portion 720 isself-etched by the TiCl₄ gas. Therefore, formation of the metal film (Tifilm) on the top surface of the insulating film 710 and the side wall ofthe penetration portion 720 is suppressed.

In addition, although it has been described that the metal film is a Tifilm and the metal silicide film is a TiSi film, the present disclosureis not limited thereto.

After the processing is completed, the controller 600 vacuum-transfersthe substrate W from the processing apparatus 103 to the load-lockchamber 301. The controller 9 of the processing apparatus 103 controlsthe lifting mechanism 24 to lower the stage 2 from the processingposition to the transfer position. The controller 600 controls thetransfer mechanism 201 and the gate valves G13 and G21 to transfer thesubstrate W from the processing apparatus 103 to the load-lock chamber301. The controller 600 controls the load-lock chamber 301 to turn theinterior of the load-lock chamber 301 into atmospheric atmosphere. Thecontroller 600 controls the transfer mechanism 402 and the gate valveG31 to transfer the substrates W from the load-lock chamber 301 to acarrier C via the atmosphere transfer chamber 400, and accommodates thesubstrate W in the carrier C.

With the substrate processing method performed by the substrateprocessing system according to an embodiment, it is possible toselectively form the metal silicide film 730 at the bottom of the recessformed in the substrate W. With the substrate processing methodperformed by the substrate processing system, it is possible to removethe amorphous silicon film 703 formed on the top surface of theinsulating film 710 and the side wall of the penetrating portion 720 bythe process of step S105. Thus, it is possible to prevent a metalsilicide film from being formed on the top surface of the insulatingfilm 710 and the side wall of the penetrating portion 720 when a metalfilm is formed on the substrate W by the process of step S107. Inaddition, it is possible to appropriately form the metal silicide film730 at a bottom portion of a recess having a high aspect ratio.

In addition, with the substrate processing method performed by thesubstrate processing system, it is possible to increase a thickness ofthe crystalline silicon film (epitaxial layer 701) formed at the bottomportion of the recess by the processes of steps S104 and S105. As aresult, it is possible to increase the thickness of the metal silicidefilm 730 formed by the reaction between the metal film and thecrystalline silicon film (epitaxial layer 701) by the process of stepS107.

As described above, with the substrate processing method performed bythe substrate processing system, it is possible to increase thethickness of the metal silicide film 730 formed at the bottom portion ofthe recess of the substrate W, and to prevent a metal silicide film frombeing formed on the top surface of an insulating film 710 and the sidewall of a penetration portion 720.

In addition, for example, when the epitaxial layer 701 is a source anddrain of a fin-type channel field effect transistor, it is possible toselectively form a contact, which is the metal silicide film 730, at thebottom portion of the recess and to control (increase) the filmthickness.

In addition, the present embodiment is also applicable to a structurehaving a recess or a penetration portion in a lateral direction as in agate-all-around field effect transistor, for example.

In addition, as for the formation of a Si film, although an embodimentin which the film formation is performed without using plasma has beendescribed, the present disclosure is not limited thereto. For example,the RF power supply 8 of the processing apparatus 101 may be applied tothe processing apparatus 102 to form the Si film with capacitivelycoupled plasma. In addition, without being limited to capacitivelycoupled plasma, for example, inductively coupled plasma (ICP), microwaveexcited surface wave plasma (SWP), electron cyclotron resonance plasma(ECP), or helicon wave excited plasma (HWP) is also applicable.

In addition, even when various materials co-exist as the material of thebase 700, that is, when a part of a plurality of recesses has bottomportions formed of Si and another part of the recesses has bottomportions formed of SiGe, it is possible to selectively form acrystalline silicon film at the bottom portion of each of the recessesand to cause the formed crystalline silicon film to react with a metalfilm. Thus, it is possible to suppress variation in film thickness ofthe metal silicide film 730.

Although the embodiments of the substrate processing systems and thelike have been described above, the present disclosure is not limited tothe above-described embodiments and the like, and can be variouslymodified and improved within the scope of the gist of the presentdisclosure described in the claims.

According to the present disclosure, it is possible to provide asubstrate processing method and a substrate processing system, which arecapable of selectively forming a metal silicide film at a bottom portionof a recess formed in a substrate.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the embodiments described herein maybe embodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosures.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosures.

What is claimed is:
 1. A substrate processing method comprising:preparing a substrate which includes a base having an epitaxial layerformed by epitaxial growth, and an insulating film formed on the baseand having a penetration portion that exposes the epitaxial layer;forming a silicon film on a surface of the epitaxial layer exposed fromthe penetration portion rather than a side wall of the penetrationportion; and forming a metal film on the silicon film formed on thesurface of the epitaxial layer rather than the side wall of thepenetration portion, and causing the silicon film to react with themetal film to form a metal silicide film.
 2. The substrate processingmethod of claim 1, wherein the forming the silicon film includes:forming the silicon film by supplying a silicon-containing gas; andremoving the silicon film formed on the side wall of the penetrationportion by supplying a halogen-containing gas.
 3. The substrateprocessing method of claim 2, wherein the forming the silicon filmincludes repeating the forming the silicon film and the removing thesilicon film.
 4. The substrate processing method of claim 3, wherein thesilicon-containing gas includes at least one selected from the groupconsisting of SiH₄ gas, Si₂H₆ gas, SiH₂Cl₂ gas, Si₃H₈ gas, and Si₄H₁₀gas, and wherein the halogen-containing gas includes at least oneselected from the group consisting of Cl₂ gas, HBr gas, and ClF₃ gas. 5.The substrate processing method of claim 4, wherein the forming themetal film to form the metal silicide film includes supplying ametal-containing gas and a reducing gas to generate plasma, and exposingthe substrate to the plasma to form the metal film.
 6. The substrateprocessing method of claim 5, wherein the metal-containing gas includesat least one selected from the group consisting of TiCl₄ gas and TiBr₄gas, and wherein the reducing gas includes H₂ gas.
 7. The substrateprocessing method of claim 6, wherein the insulating film is SiN orSiO₂, and wherein the epitaxial layer contains Si or SiGe.
 8. Thesubstrate processing method of claim 7, further comprising, before theforming the silicon film, removing an oxide film formed on the surfaceof the epitaxial layer exposed from the penetration portion.
 9. Thesubstrate processing method of claim 8, wherein the removing the oxidefilm, the forming the silicon film, and the forming the metal film toform the metal silicide film are performed without breaking a vacuum.10. The substrate processing method of claim 2, wherein thesilicon-containing gas includes at least one selected from the groupconsisting of SiH₄ gas, Si₂H₆ gas, SiH₂Cl₂ gas, Si₃H₈ gas, and Si₄H₁₀gas, and wherein the halogen-containing gas includes at least oneselected from the group consisting of Cl₂ gas, HBr gas, and ClF₃ gas.11. The substrate processing method of claim 1, wherein the forming thesilicon film includes simultaneously supplying a silicon-containing gasand a halogen-containing gas.
 12. The substrate processing method ofclaim 1, wherein the forming the metal film to form the metal silicidefilm includes supplying a metal-containing gas and a reducing gas togenerate plasma, and exposing the substrate to the plasma to form themetal film.
 13. The substrate processing method of claim 12, wherein themetal-containing gas includes at least one selected from the groupconsisting of TiCl₄ gas and TiBr₄ gas, and wherein the reducing gasincludes H₂ gas.
 14. The substrate processing method of claim 1, whereinthe insulating film is SiN or SiO₂, and wherein the epitaxial layercontains Si or SiGe.
 15. The substrate processing method of claim 1,further comprising, before the forming the silicon film, removing anoxide film formed on the surface of the epitaxial layer exposed from thepenetration portion.
 16. The substrate processing method of claim 15,wherein the removing the oxide film, the forming the silicon film, andthe forming the metal film to form the metal silicide film are performedwithout breaking a vacuum.
 17. A substrate processing system comprising:a first processing apparatus configured to remove, with respect to asubstrate which includes a base having an epitaxial layer formed byepitaxial growth and an insulating film formed on the base and having apenetration portion exposing the epitaxial layer, an oxide film formedon a surface of the epitaxial layer exposed from the penetrationportion; a second processing apparatus configured to form a silicon filmon the surface of the epitaxial layer exposed from the penetrationportion rather than a side wall of the penetration portion; and a thirdprocessing apparatus configured to form a metal film on the silicon filmformed on the surface of the epitaxial layer rather than the side wallof the penetration portion, and cause the silicon film to react with themetal film to form a metal silicide film.